RE: Is it allowed? Unfortunately, yes. - Ist es erlaubt? Leider ja

I think market price should be more fixed within the day but anyone selling anything has the right to change their price to their own products at any given time.

Maybe in the future the price will go up and down as your pumping your gas, and hope to God you win the lottery of having it spike up a dollar mid flight. Such joyous days when gas prices rise above the roof.